Generally speaking, in order for barcode readers and barcode scanners to operate properly, it may be necessary in some situations that a code (e.g., a barcode) is well lit. When natural light is insufficient to properly illuminate an object, various types of illumination devices may be used in conjunction with the barcode readers and barcode scanners to light different types of barcodes. The type of illumination needed may be a factor of the type of surface on which the barcode is applied. Also, various objects may have different types of barcodes that may be applied in a number of different ways.
One type of code applied to an object is a direct part marking (DPM) code, which is a code that is permanently applied to the object. The DPM codes may be dot peen markings formed on the surface of the product or other types of permanent codes. To properly illuminate a DPM code, it may be necessary to light the code with dark field illumination, which is an illumination technique in which light is directed at a high angle of incidence on the surface of the object, or in other words, directed at a shallow angle with respect to the object's surface. The surface characteristics of a DPM or dot peen marking can be more easily deciphered by a barcode reader or barcode scanner when dark field illumination is applied.
Other surfaces, such as those that are non-reflective and include a flat profile, may instead be better deciphered when bright field illumination is applied. Bright field illumination includes light directed in a way such that the light is at a low angle of incidence with respect to the surface, or in other words, is directed in a substantially perpendicular direction with respect to the object's surface.
Therefore, a need exists for illuminators and other types of illumination devices for providing light directed in a manner that includes both dark field illumination and bright field illumination. Thus, optical imaging devices (e.g., barcode readers, barcode scanners, or other sensing devices) can more accurately decipher the barcodes and other types of codes.